In recent years, an electric vehicle (EV) is widely used. The electric vehicle is configured of a combination of a rechargeable battery and a motor, and it is necessary to suppress consumption of accumulated power because energy needs to be replenished from an external charger, basically. In this respect, in order to suppress power consumption for heating (air conditioner) performed by high power consumption, a section is provided to cause warmth to be directly transmitted by a steering wheel that is directly touched by an occupant (driver). For example, a heater line as a heating element is buried in the steering wheel, and thereby it is possible to warm the steering wheel even when it is not long after a start, and various engines are not sufficiently warmed. Hence, when an automobile as a vehicle parked outside in winter is started and driven, for example, it is possible to suppress use of heating and suppress power consumption while there is a reduction in difficulty or discomfort of an operation due to a cold steering wheel.
As such a configuration, a steering wheel is known in which a heater unit provided with layout of a heater line on a strip-shaped sheet element is wrapped around an outer circumference of a rim section of a cored bar or the like formed of a steering wheel base material and is further covered with an outer skin element such as genuine leather (for example, see PTL 1).